PhD Scientific Days 2023

Molecular Sciences IV.

The Role of the Myeloid Src-family Kinases in Nephrotoxic Nephritis

Text of the abstract

Introduction: Murine nephrotoxic nephritis is a widely used model of immune complex-mediated glomerulonephritis. In this model, mice are immunized with normal sheep IgG, followed by administration of a sheep antiserum (nephrotoxic serum or NTS) raised against mouse glomerular components. This leads to glomerular injury. The Src-family kinases Hck, Fgr, and Lyn are critical for various disease models. However, their role in kidney diseases is poorly understood.
Aims: We aimed to test the role of Hck, Fgr, and Lyn in the development of nephrotoxic nephritis.
Method: Wild-type, Hck−/−Fgr−/−Lyn−/− triple knockout and Hck−/−, Fgr−/− or Lyn−/− single knockout mice were preimmunized with sheep IgG followed by intravenous injection of NTS or normal sheep serum. On the fourteenth day, urine was collected over a 24-hour period. After an additional day, blood was collected, the kidneys were removed, and the leukocyte infiltration and the glomerular injury were tested by flow cytometry and light microscopy. Hck−/−Fgr−/−Lyn−/− and wild-type bone marrow chimeras were generated to narrow down the cell types where these kinases are important.
Results: Wild-type NTS-treated mice developed severe albuminuria (approx. 4 mg/day) on the fourteenth day. Crescents were present in approx. 10% of the glomeruli of these mice, with additional histological signs of glomerulosclerosis. Flow cytometric analysis has revealed massive leukocyte infiltration of the kidneys. Serum creatinine levels were two times higher in NTS-treated than in control mice. In contrast to wild-type mice, NTS-treated Hck−/−Fgr−/−Lyn−/− showed normal serum creatinine levels, dramatically reduced albuminuria, and no substantial histological abnormalities. Analysis of Hck−/−, Fgr−/− and Lyn−/− single knockouts have revealed substantial protection of Hck−/− mice from disease development, whereas the Fgr−/− and Lyn−/− are still susceptible to induction of nephrotoxic nephritis. NTS-induced albuminuria was partially reduced in chimeric mice generated by transplantation of Hck−/−Fgr−/−Lyn−/− bone marrow cells into wild-type recipients.
Conclusion: Our results indicate a crucial role for myeloid Src-family kinases, in particular the Hck tyrosine kinase, in the development of immune complex-mediated glomerulonephritis. Src-family kinases are likely important, at least in part, in a radiosensitive hematopoietic compartment.
Funding: „Semmelweis 250+ Kiválósági PhD Ösztöndíj” EFOP-3.6.3-VEKOP-16-2017-00009